Oxidant-Controlled Stereoselectivity in the Pd-Catalyzed Allylic Oxidation of cis-Vinylsilanes
摘要:
The allylic oxidation of cis-vinylsilanes is reported. The reaction requires a low catalyst loading of Pd(OAc)(2) without the need for an external ligand. Interestingly, trans-vinylsilanes are unreactive, whereas allylic oxidations of cis-vinylsilanes proceed in good yields giving a single diastereo- and regioisomer of the branched allylic acetate trans-vinylsilane when benzoquinone is employed. The use of PhI(OAc)(2) as oxidant in place of benzoquinone provides the branched, cis-vinylsilane as the major product. Additionally, the first intramolecular allylic C-H etherifications of cis-vinylsilanes to give oxygen heterocycles are also described.
A series of novel monothiolate-bridged dirhodium complexes, [Cp*Rh(μ-SR)(μ-Cl)2RhCp*][BF4] Cp* = η5-C5Me5, R = tertiary butyl (tBu), 1a; R = ferrocenyl (Fc), 1b; R = adamantyl (Ad), 1c} were designed and successfully synthesized, which can smoothly facilitate highly regioselective and stereoselective hydrosilylation of terminal alkynes to afford β(Z) vinylsilanes with good functional group compatibility
Oxidant-Controlled Stereoselectivity in the Pd-Catalyzed Allylic Oxidation of <i>cis</i>-Vinylsilanes
作者:Christopher T. Check、William H. Henderson、Brenda C. Wray、Matthew J. Vanden Eynden、James P. Stambuli
DOI:10.1021/ja2089102
日期:2011.11.23
The allylic oxidation of cis-vinylsilanes is reported. The reaction requires a low catalyst loading of Pd(OAc)(2) without the need for an external ligand. Interestingly, trans-vinylsilanes are unreactive, whereas allylic oxidations of cis-vinylsilanes proceed in good yields giving a single diastereo- and regioisomer of the branched allylic acetate trans-vinylsilane when benzoquinone is employed. The use of PhI(OAc)(2) as oxidant in place of benzoquinone provides the branched, cis-vinylsilane as the major product. Additionally, the first intramolecular allylic C-H etherifications of cis-vinylsilanes to give oxygen heterocycles are also described.